Biodiesel revisited

[sailmed]

Just did a search of the forum, and I see that the last post re: biodiesel is about a year old.  I, for one, would love to be able to use a renewable fuel that I can buy from our US farmers, rather than from the Middle East or Venezuela.  Anyone with new ideas, prospects, or experiences?

[Stu Jackson]

Barry

It's pretty much a local issue, because if it isn't available near you it becomes difficult to justify unless you're either driving by the distributor or sailing to where it is available.

For instance, here in the Bay Area, it used to be available at a fuel dock in Richmond, which is somewhere I rarely travel by boat.  I believe that has been discontinued.  The only other source I know of is in Berkeley, requiring a car trip and fueling from jugs, with all that entails.

I only wish it WAS more readily available.

[Terry Forshier]

Here in SW floridaa I found a person on Captiva selling biodiesel out of barrels at this house. Last year I bought about 20 gallons, mixed it with my regular diesel and used it all summer. It did burn with less smoke and also used a little more fuel. I was told that I would need to change lines or filters but did not have to. My old Yanmar ran well on it and my transom did not get black with smoke stains.
Most people I have asked around here find some reason not to use it but for me It worked well and did not smell or smoke like diesel oil does.

[sailmed]

Terry:

Just for interest, what proportions of biodiesel to "petrodiesel" did you use?  Did you ever try pure biodiesel?

Thanks.

[David Sanner]

I've heard that if you burn over the normal 80/20 (dinosaur/vegi) mix you could have
problems with your engine seals, older fuel hoses, etc. 

This is for an engine that's been running regular diesel... if you are starting out with zero
hours you can run a much higher mix.  (Apparently regular diesel can make your seals
swell. The problem comes from then running pure vegi biodiesel and having them then shrink)

I've also read that biodiesel can help clean up your engine... ie remove deposits in the
cylinders, free up stuck rings, and can also help clean your injectors.... all that while
making the exhaust smell like french fries.

Now finding a good source is another issue.

[Terry Forshier]

True for all the above. I used an 80/20 mix with the biodiesel at 20%. I kept waiting for the french fries to smell but really it was alittle like popcorn. I think this biodiesel was made from old grease and not from midwest grain (soy beans I think) I noticed that the engine ran well, smooth, and I felt it had cleaned out the cylilnders of the sludge from my 1979 2QM15 Yanmar.
It really ran well all last year and did not smoke when I pushed it. the old diesel fuel would leave a black smoke stain on the transom and it was hard to clean off. It was a direct salt water cooled system. I used a gallon of diesel every 2.5 hours at 5kts or 2200 rpm. With the biodiesel it went to about a gallon per 2 hours.
The seller , who was a charter captain on an older Pearson, out of Captiva said he ran pure biodiesel. He did , though, change all his fuel lines and filtters after the first few tanks.
I took several trips of 100+ miles a whack with the bio blend Like from Naples to the Dry Tortugas and back and to Key West and Marathon and back. All about 100 miles each way all across Florida Bay. Most of these trips were motoring in the soft summer winds we get in Florida.
I was paying close attention as I was dodging some of the exciting weather we have had here in SW FLorida. Fortunatly one of the big blows we were in convinced my wife we needed a bigger boat. (that is another story)Thus, we now have our Catalina 34 and not the O'Day 30 that we sailed for 20 years. This was a real nice step up for us.
Terry

[Ron Hill]

Barry : You can go with 100% bio-diesel, but you need an additive to lube the injectors and injection pump.  The hoses should be OK.
The biggest problem that I found was it was sold in 5 gal containers(you had to buy the prepackaged container) and at that time it was 4 or 5 times the price of regular diesel - but that may have changed now.
Hope this helps. 

[Ken Heyman]

Interestingly (if not on point) the Discovery Channel show "Myth Busters" compared regular diesel vs.  used filtered cooking oil that they secured from restaurants. They tested mileage at a constant speed over a controlled course in a Mercedes " Diesel" As I recall, the regular diesel produced mileage of 33 mpg vs 30 mpg for the cooking oil trial. I didn't see it all but I don't think they talked about performance or maintenance issues. The cost was obviously less since the oil was a throw away item from the restaurants. ----not terribly practical but interesting particularly for a large user of fuel.
I do prefer the smell of popcorn to diesel exhaust so perhaps this one day may be a motivator. There has also been speculation regarding carcinogenic properties of diesel fumes. I'm not sure about cooking oil.

Ken

[Mike Smith]

I heard a report this morning on NPR on using used vegetable oil (not a biodiesel mix) and it really makes sense.  It does require modification to your engine, though.  At the end of the report, the narrator commented that if you didn't like using used vegetable oil, just go to Walley World and check what a gallon of vegetable oil costs relative to the cost of a gallon of diesel!  It's cheap!  Could be a problem offshore or in exotic locations!

Mike

PS  Terry... a properly tuned diesel engine shouldn't smoke - the exhaust should be colorless!  If it's consistently white, there is water in the fuel system, if it's black there is incomplete combustion, and if it's blue you're burning engine oil.  Not good!

[Robert Mann]

There are several different types of "bio diesel".  There is a 100% pressing of some oil bearing seed, such as Rape Seed in Europe or Soy Bean in North and South America.  If used in the neat form heavy coking occurs, this is due to the lack of evaporation.  Typically this type of fuel works in indirectly injected engines, but not directly injected engines.  The failure rate of test engines operating on this fuel is high, with injection equipment failures, stuck exhaust valves and some cases piston seizures.

The other main type of bio diesel is made using a process where the Rape or Soy oil is refined using methanol which converts  the glycerol molecules, don't ask me how, far too much chemistry involved for me!  The finished fuels are know as Methyl Esters.  These are added at a 20% rate to regular diesel fuel and sold as bio diesel.

With the second case there are some issues to watch, power reductions will occur and the engine should not be up fuelled to compensate, lube oil changes should be halved, engines should be run on regular diesel before being laid up for the winter.  Fuel system rubber pieces will be affected, seals in the filters, transfer pump diaphragms, hoses etc and these need to be checked and replaced regularly.

The other bad part is; this fuel will absorb water more than diesel, so algae and bacteria growth can be high.  The marine environment is not the best for this. 

Advantages:

Lower soot and particle emission, lower sulphur content creates less SO2, lower aromatic compounds.

Disadvantages:

reduced oil change period, reduced output, increased fuel consumption 7% - 10%, increased nitrous oxide emission

The end all I know.